Sagging Voice Coils?


I was just reading a thread on AA where someone mentioned that one should rotate bass drivers to prevent the voice coils from sagging. It sounds like a problem for geriatric speakers, but is there any truth to this?
bojack
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These were built in the '90s, and they knew about the sag problem then. [http://www.roger-russell.com/xl1w.htm]
You might notice; that article, and it's accompanying remedies, addresses downward facing woofers only(as in some subwoofers). Many of which have heavy cones and/or long excursion(some double) coils. The effect of that type of sag would displace the voice coil, from it's centered/at rest position.